Lignocellulose product and method



United States Patent LIGNOCELLULOSE PRODUCT AND METHOD William T. Glab,Dubuque, Iowa, assignor, by mesne assignments, to Durel Incorporated,Dubuque, Iowa, a corporation of Iowa No Drawing. Filed Sept. 25, 1958,Ser. No. 763,193

17 Claims. (Cl. 106-163) This invention relates to a method of making alignocellulose reaction product composition and to the resultingcomposition.

One of the features of this invention is an improved method of making amoldable lignocellulose reaction product in which the lignocellulose isreacted with a chloride catalyst in the presence of moisture while thereacting mass is confined under superatrnospheric pressure in anautoclave to produce a product that may be molded under heat andpressure or that may be extruded to form shaped products.

Another feature of the invention is to provide such an improved methodwherein the reacting mass may contain in addition to the chloridecatalyst other reactants and modifying agents including lignin, Vinsol,phenols, organic acids, sulfur, unsaturated organic compounds, alcohols,or the like or any other desired modifying agent so that thecharacteristics of the resulting moldable product may be varied asdesired.

A further feature of the invention is to provide improved moldableproducts prepared according to the method of this invention.

In this invention, finely divided lignocellulose is reacted in thepresence of moisture with a chloride catalyst at an elevated temperatureand under superatmospheric confined pressure to produce the moldable andextrudable composition. The chlorides which operate as the catalyst maybe either inorganic or organic and appear to operate as destructivecatalysts in that they are themselves broken down during the reaction.However, they appear to be self-generating, as the improved moldablecompositions are prepared even when only a small amount of the catalystof the order of 0.1% by weight of the lignocellulose or less is used.Thus observations and tests have indicated that 'the chloride operatesas a true self-generating catalyst and therefore any of a very largenumber of catalysts are indicated as being useful to produce the resultsof this invention. For example, alkali,

metal chlorides, ammonium chloride, alkaline earth metal chlorides,transition metal chlorides, chlorides of the third and fifth sections ofthe periodic table, as well as organic chlorides are usable.

All of the chlorides that have been tried have been found to producethis catalytic effect. These are potassium chloride, ammonium chloride,magnesium chloride, calcium chloride, manganese chloride, zinc chloride,copper chloride, iron chloride, aluminum chloride,

7 titanium chloride, and acetyl chloride. Because the c'hlo I rides actas a catalyst to promote the reaction in the high pressure reactionvessel, the choice of. the chloride is vast.

An important advantage of the invention appears to be the controlobtained over different reactions, by choosing the proper chloride, toobtainva wide variety of products. The generalactivity of thesecatalystsappearsto be of the following decreasing order: titanium aluminum cu-.pric ferric acetyl ammonium ferrous zinc m angia- 1 nes'e niagnesiumcalcium potassium.

In actual practice it has been found that in most instances the amountof chloride catalyst used will vary between 01-50%, with the preferredamount being 0.1- 20%. The pressure that has been most generally used isone between about 25-700 pounds per square inch gauge, with a range ofabout -500 pounds per square inch being especially preferred. Thetemperature of the reaction is generally between about 250-500 F., withthe range of about 275-475 F. being especially preferred. The time ofreaction will, of course, vary depending upon the particular chloride ormixture of chlorides used as a catalyst, but in most instances has beenfound to be between about 4-60 minutes.

The reaction product prepared with these catalysts can be modified byincluding in the reacting mass modifying agents or mixtures thereof.Modifying agents that have been found particularly useful includelignin, preferably in an amount between about 2-30%; Vinsol, preferablyin an amount of about 2-30%; 21 phenol such as either phenol or cresol,preferably in an amount of about 1-20%; liquid fatty acids such asbutyric acid, or Tall oil, preferably in an amount of about 05-50%;sulfur, preferably in an amount of about 05-20%; unsaturated organiccompounds such as dicyclopentadiene or styrene, preferably in an amountof about 05-30%; alcohols, such as isopropyl alcohol or glycerine,preferably in an amount of about 2-30%.

The catalyst of this invention converts the raw lignocellulose to aresinous material which is compatible with synthetic resin systems toproduce shaped products of desired characteristics. The resinousmaterial formed with the catalyst of this invention can be used as waterrepellent binders for either organic or inorganic fillers in moldingcompositions. Observations have indicated that the presence of thecatalysts in the high temperature and superatmospheric pressureconditions in the presence of moisture causes an increased reaction rateof hydrolysis, esterification, alkylation, or polymerization of thelignocellulose itself. Furthermore, it appears that the presence of thechloride catalyst actually lowers the time, temperature and pressurerequirements for bringing about such reactions in a superatmosphericpressure system and also increases the yield of themold able product. Itappears that the catalyst catalyzes the break- 7 the catalyst causes abreaking of the lignocellulose bond to provide lignin and that thealphacellulose is depolymerized to .makethe product resistant tomoisture and also that a portion of the hemicelluloses are con verted tohigh molecular weight resins that may 'be molded;'extrude,d,,orotherwise used, similar to the ordinary molding resins. The reactionswhich appear to take place in the high pressure reacting mass alsoappear to include esterification, or alkylation, or alcoholic groupspresent to modify further' the properties of the ligno;

. cellulose.

The lignocellulose that is'used is essentially dry to the touch. Suchlignocellulose may contain up to about 30%by weight of'water and stillfeel dry. v "In the method of this'inventionlan essentially dry mixtureincluding comminuted lignocellulose and a chloride capableofcatalyzingboth the breakdown of at leasta a portion. of the lignocellulose toprovide ligninor 7 fied lignin, and of reforminga part of the.her'nicellulose leased to operate as a binder. It appears that thelignin is also modified, possibly by a reduction of the crosslinkingbetween the lignin molecules; since the product is formable in the250-300 F. temperature range, indicating a reduction in the meltingpoint 'of the lignin, and hence in molecular size.

Depending upon the conditions and reactants utilized, one or severalreactions can be carried out simultaneously. For example, if steam, inthe presence of a chloride, is used as a reactant, as well as, a heattransfer medium, the controlling reaction will be hydrolysis. Underthese conditions, it appears that the hemicellulose is the primaryconstituent of the lignocellulose which is attacked, but that under thehigh pressure and temperature of this invention, a portion of thehydrolys'ate isfurther converted to higher molecular weight materialswhich can function as plasticizers for the autoclave product when it ismolded, or otherwise formed.

At the same time, the hemicelluloses are being reformed, a controlleddepolymerization of the alpha-cellulose is apparently carried out to theextent that the desired degree of moisture stability is obtained in themolded or formed products, without an unnecessary loss of toughness. Thechloride functions as a catalyst for both this depolymerization, as wellas, the repolymerization of the hemicellulose hydrolysate. These actionsare believed to occur although they have not been absolutely proven.

The chlorides have also been found useful in promoting specificlignocellulose reactions which result in autoclaved products withimproved moisture resistance, thermoplastic flow and bonding tendencies.Typical of these reactions are esterfication using acids such as Talloil and butyric. Alkylations of the lignocellulose with both alcoholsand olefins are promoted by" the chlorides, and can be used to introducedifferent alkyl groups, and thus further vary the properties of theproduct. These reactions can be carried out simultaneously in thepresence of steam, along with the partial hydrolysis, and polymerizationof hydrolysate fractions, to produce materials having a wide range ofproperties.

The high pressure method of this invention has a number of advantagesthat are not possible with reactions taking place at ordinary pressuresand in an unconfined state. In the preferred process, steam isintroduced into the autoclave both for heating purposes, and to supplymoisture for the reaction. With high pressures, heat transfer is muchmore rapid; so that in general a shorter reaction time is required.

Furthermore, in a closed system energy losses during the reaction aregreatly reduced. In the ordinary reacting mixture these energy. lossesresult from the release of volatile materials such as water vapor,gaseous reaction by-products and the like. As the reaction here takesplace in a confined atmosphere, no such losses occur to any materialdegree.

Another important advantage of this process is the close control that isobtained over the reaction. Thus the temperature of the reacting mass,and hence the rate of reaction can be easily raised or lowered bycontrolling the rate of flow, pressure and temperature of the heattransfer medium which may be steam, oil vapor or other high temperaturefluids. Reactions can easily be stopped by flashing the heat transfermedium from the autoclave;

since the large energy loss on expansion cools the reacting mass belowthe incipient reaction point. During the practice of the process, thereacting mixture may be confined in a jacketed vessel with the heatingmedium introduced to the chambers in the quantity and at the temperaturedesired.

Tests have shown that the confining of the reacting mass in theautoclave not only causes retention of the byproducts of reaction withinthe mass, even when the byproducts are gaseous, but also causespolymerization of all or a portion of theseby-productsf p V Anotheradvantage of the invention is'that the" volatile 4 by-products do not gointo solution as in wet processes, but are easily collected and removedat low cost for later use, where desired, or to prevent the creation ofa nuisance.

A very important advantage of the invention is that volatile reactantsmay be used, as the reacting mass is in a confined space. Volatilereactants are impractical, of course, when the reacting mass is in theopen. As a result of the rapid heat transfer achieved by this invention,and the penetration of volatile reactants, the reaction not onlyproceeds to completion in a much shorter time, but the final producttends to be more uniform than where the reactants are heated, such as inan ordinary process that depends upon surface temperature differentials.

Where the reactants are volatile, no mechanical mixing of theingredients is required. This results in a considerable saving in time,labor and other factors. Thus, in these instances, it is only necessaryto charge the reactor with the lignocellulose and introduce the volatilematerials into the reactor under superatmospheric pressure. In addition,if desired, the reactants can be changed or modified during the courseof a run. This is not possible to such a degree in a wet process wherethe charge generally contains less than 50% of lignocellulose, andaddition of reactants would in many cases cause prohibitive amounts togo into solution.

A further advantage of utilizing a vapor process is that the volatilecontent of the reaction product, which is primarily moisture, can becontrolled. By using superheated steam with a suflicient degree ofsuperheat, prod ucts on the order of 1% volatile content can beobtained. Under normal conditions 25 degrees of superheat at 300 poundsper square inch steam pressure will produce a product of 5-8% volatilecontent. Thus the expensive drying step connected with wet processes canbe avoided.

Because of rapid penetration of reactants under high pressure, largersized particles of lignocellulose can be charged to the autoclave thanwould ordinarily be used, and a savings in size reduction cost made, asa result of lower power requirements to reduce the treated material incomparison with raw lignocellulose.

The methods of this invention may be carried out batchwise in anautoclave or a sealed press, or continuously in a continuous contactor.

The lignocellulose which may be used in this invention includes wood aswell as other lignocellulosic vegetable materials. The lignocellulose isfinely divided; so that the particles are preferably not more than Amesh in average size as measured by a standard screen.

Where the reactant is steam, this steam is preferably supplied to theautoclave or other confined reactor at a temperature of 250-500 F., andthe reaction is permitted to proceed for from 4-60 minutes. In general,the longer periods of time are used with the lower temperatures, whileshorter periods are required with higher temperatutes.

The steam may be saturated or superheated, and may be at a pressure ofbetween 25-700 pounds per square inch gauge. In the preferred processthe temperature of the steam is between 275 -475 F., and between 50- 550pounds per square inch gauge. The choice of steam pressure, andtemperature, for any particular reaction will depend upon the chlorideused as a catalyst. In general, the higher temperatures and pressuresare used with the catalysts having the least activity as previouslylisted. and the lower temperatures and pressures are used for the mostactive. Thus with potassium chloride the lowest pressure generally usedis 300 pounds per square inch gauge, while withalurninumchloride 300pounds is usually the maximum pressure applied.

I Both the steam pressure and duration of reaction are dependant uponthe specific chloride used. In addition, the time andpressuredependjupori the quantity; of chloride employed as a'catalyst.'In"ger'iefa1"tli relationship between steam pressure, time of'reaction,and the amount of the different chlorides required as catalysts toproduce products of approximately equivalent moisture resistance isillustrated in the following table of examples using saturated steam.The examples are arranged according to the decreasing activity of thecatalyst. In each of the following examples, the specified chloride inthe amount required was mixed thoroughly with ordinary sawdust. Themixture was introduced into the reacting autoclave and steam wassupplied to the interior of the autoclave at the pressure stated and forthe time stated. At the end of the reaction time, the mass was removed,broken up and was found to be a powder having resinous characteristicsthat could be shaped, such as by molding or extruding, to a desiredform.

In the practice of this invention, the catalysts are dissolved in eitherwater or an organic solvent, and then added to the lignocellulose. Thesolvent functions to disperse the catalyst throughout the mass of thelignocellulose. The amount of the solvent used, which is preferablywater, is generally between 5-30% of the weight of the lignocellulose. I

The quantity of catalyst employed is dependent upon its activity, aslisted in Table I. In general the catalyst is used in an amount between01-50% by weight of the lignocellulose depending upon the type ofreaction. With one of the most active chlorides, alumimun, as little as0.1% is effective in some reactions; while with the less active, muchlarger quantities are required. In the preferred process the catalyst ispresent in an amount equal to between 0.1%-20.0% of the weight of'thelignocellulose. In addition to the activity, specific reactions mayrequire more or less of a given catalyst.

The chlorides employed as catalysts may be titanium, aluminum, cupric,iron (ferric), acetyl, ammonium, iron (ferrous), zinc, manganese,magnesium, calcium, and potassium. In the preferred process thecatalysts employed are aluminum, iron, acetyl, ammonium, zinc, calcuim,and magnesium. Ingeneral, aluminum and iron chlorides are of a higherorder of activity than are acetyl, ammonium and zinc, which are lessactive. Calcium 7 and magnesium are the least active, and similarlyareof the same degree of activity.

In the practice of this invention it has been found that very moistureresistant materials can be produced by reacting lignocellulose withsteam inthe presence of a chloride. -In addition, the chloridespromotereactions between lignocellulose and high molecular weight aro-' maticmaterials such as Vinsol, phenolic residue and lignin; they catalyzeboth esterification reactions with fatty acids such as Tall oil,andlignocellulose condensation with phenols, and they promote diversereactions such as between sulfur and lignocellulose,,anddicyclopcntadiene and lignocellulose. Thus a wide variety of materialcan be produced depending upon the choice of reactants.

Thepreferred reactants used in conjunction they are preferably finelydivided to a particle size that is preferably no more than mesh on astandard screen. In the preferred process each of these reactants,Vinsol, phenolic residue or lignin is used in an amount between2.0-30.0% by weight of the lignocellulose. Such additives are preferablythoroughly blended with the lignocellulose in a mixing device such as aball-mill, and then the liquid catalyst is added to the mixture, whichis then further agitated to uniformly disperse the catalyst throughoutthe blend. The specific reaction time and the reaction temperature willdepend upon the chloride chosen as the catalyst, but in general it isabout the same as that given above in connection with steam alone as thereactant.

The preparation and characteristics of Vinsol are set out in mycopending application Serial No. 608,196, filed September 6, 1956, nowpatent No. 2,872,330, issued February 3, 1959.

Where lignocellulose is condensed in the presence of steam with a phenolsuch as cresol or phenol, it is preferably used in an amount between120% by weight of lignocellulose. Liquid phenol or cresol is first addedto the comminuted lignocellulose, and they are thoroughly blendedtogether in a ball-mill or other mixer prior to the addition of thecatalyst. Similarly to the other reactants, the reaction time andtemperature depend upon the specific chloride used as a catalyst.

Where acids, such as Tall oil are used to esterify the lignocellulose inthe presence of steam with a chloride as a catalyst, they are preferablyused in an amount between 05-50% by weight of the lignocellulose. Thesereactants likewise are preferably blended with the lignocellulose beforethe addition of the chloride. When very small quantities are employed,however, they can be emulsified in the catalyst solution, and added atthe same time. Again, as with the other reactants, the temperature, andduration of reaction, are dependent upon the specific catalyst. V

Where sulfur is the reactant in conjunction with steam, the sulfur ispreferably finely divided to a particle size that is preferably no morethan 100 mesh on the standard screen. An especially preferred range ofparticle, size is between 200-300 mesh. In the preferred process thesulfur is used in an amount between 05-20% by weight of thelignocellulose. The reaction time and the rethe specific chloride usedas the catalyst.

When unsaturated organic compounds such-as dic'yclo I pentadiene arereacted with lignocellulose, they are prefer ably blended before theaddition of the catalyst. The

preferred amount of dicyclopentadiene is between 05-30%" by weight oflignocellulose. The reaction time and temperature again depends on thechloride cat-alyst-, but is in general approximately the same as thatgiven for steam. 5 I 7 When alcohols such as isopropyl alcoholorglycerine v are used, the preferred'aniount is, about 2 30%.

The materials producedby 'this'inventio'n can v to produce a variety ofproducts; The materialscan formed into boards in a press, and molded orextruded f into any desired shape. They possess far superior waterresistance comparedto conventional*lignocellulose materials, and theyare formableat a low temperaturesuch;

as in the approximate range of 275 to,.=.325 F. without the use ofexcessive pressures. The temperature at which 3 p the materials are'formedis'not critical, however,since; boards can easily be made at400F.or higherEif ;de-'- sired. The ability tOL fOIfm-PfOdUCtS at lowertemperature-is an important property since many of the synthetic;thermoplastic resins, formable' at this; temperature thus be blendedwith the modified iht desired to further change the physical propertiesof the product.

Products can be produced over a wide range of density from approximately0.5-1.5 depending upon the temperature and pressure used. The pressuresutilized'can vary from 25-5000 p.s.i. depending upon the moldingtemperature, and the final product density desired. In general, thelower pressures are used at the higher temperatures. Where boards orpreforrns (a lightly compressed selfsustaining mass) are produced thepressure is generally between 25-800 p.s.i. and temperature between300-400 F. If the materials are molded or extruded the higher pressuresare used, and the temperature ordinarily required is between 275-350 F.

When boards or preforms are made the particle size is preferably betweeninchl mesh as measured on a standard screen, but it will depend upon thefinal board density, and associated properties desired. The preferredparticle size is between 20-50 mesh. The press time is only suificientto cause the particles tocoalesce and bond to each other and to reachthe desired board density. The time will, of course, vary with theapplied pressure, press temperature, and with the material used as wellas the thickness of the finished board. In general, the press time isbetween 0.220 minutes. A V4 inch thick board can ordinarily be made in6-8 minutes, at a temperature of 350 F. and under 100 psi. pressure.

Where the reaction products of this invention are molded or extruded,the product is preferably removed from the reaction vessel, and thenground to a powder that is preferably not over 50 mesh in size. Thefinely divided moldable material is heated to a temperature justsufficient to flow and fill the mold, or to extrude through a die underthe pressure used. The molding time is only sufficient to cause themoldable material to fill the mold, and set, and will vary dependingupon the type of mold being used, the temperature, the nature of themoldable material, and similar factors. In general, the molding timewill vary between 02-15 minutes.

If desired, fillers or fibrous materials can be blended with thereaction products to achieve desired physical properties. Among thefillers that have been used are wood flour, mica, diatomaceous earth,pearlite, and silica. They are preferably used in quantities up to 25%of the weight of the lignocellulose reaction products. The exact amountof 'each filler used is, of course, dependant upon it bulk density,thephy sical properties required of the product, and the ability of thespecific reaction product to wet and bond the filler. The fillers arepreferably finely divided and in general not coarser than 20 mesh asmeasured on a standard screen. Where nonporous mineral fillers are used,they are preferably not coarser than 100 mesh.

When fibrous materials are blended with the reaction products, they arepreferably used in quantities up to 25% of the Weight of the reactionproduct. The quantity employed will again depend upon the natureof thefiber, the specific reaction product, and the physical propertiesrequired in the formed products. Among-the fibers which have beenemployed are asbestos, hammermilled sawdust, glass, Silvacon (finelydivided tree bark), cotton, bagasse, and pulped wood. I

In-general, mineral fibers and fillers produce high density productswith very low moisture absorption. However, materials such as; pearlitecan be used wherea lower density is desirable. The organicadditives'increase the moisture absorption, but within the limits givenabove,'do not seriously aifect the dimensional stability. Organicfillers can be used toreduce the density'of the products.

Example 16 'To 500 grams of 20 mesh, hammermilled Ponderosajpinegcontainiri g only its edema moisture pontentf of .a'p-

proxiniately 6% iivas add cd 100 grains of m /{perish aqueous solutionof aluminum chloride. Based on the weight of the lignocellulose theamount of solution was approximately 20% and the aluminum chloride wasapproximately /2%. The mixture was ball-milled for /2 hour to obtain auniform dispersion of the aluminum chloride throughout the mass. Thiscomposition was then placed in a heated autoclave and saturated steamwas admitted until the pressure was 300 pounds per square inch gauge,and the temperature was approximately 425 F. The autoclave was heldunder these conditions for 20 minutes and then the steam was rapidlyflashed off. During the course of the run, the pressure was maintainedat 300 p.s.i. by venting off the excess pressure caused by volatilereaction by-products. The granular reaction product, which had beencooled below the incipient reaction point by the rapid steam flash-off,was removed from the autoclave and all particles which had consolidatedwere thoroughly broken up. The moisture or volatile content of thismaterial was approximately 10%.

In the same manner as specified in Example 16, reaction products oflignocellulose and steam in the presence of catalytic amounts of each ofthe chlorides of titanium, manganese, copper, iron, ammonium, zinc,calcium, magnesium, potassium and acetyl were prepared. The followingtable sets forth the quantity of chloride used, based on the weight ofthe lignocellulose, the reaction time, and the autoclave conditionsmaintained during the reaction.

TABLE II Percent Autoclave Chloride Reaction Example Chloride Used,Time,

Percent Min. Temper- Pressure,

ature, F. p.s.i.

0.25 15 350 2.00 20 300 1.00 20 .40 300 1.00 15 440 300 2.00 15 400 2001.00 20 4-10 300 1.00 15 4-10 300 2.00 20 440 300 1.00 20 440 300 2.0020 1 10 300 27 Magnesium"- 2.00 20 440 300 28 Potassium- 2.00 25 440 30029 Aoetyl 1.00 20 440 300 The above percentages are by weight of thelignocellulose and the pressures are gauge pressures.

To determine the effect of the chlorides on the lignocellulose-steamreactions, several controls were run similarly to Examples 1629, inwhich plain lignocellulose was reacted with steam. The reaction timesand autoclave conditions are given in Table III.

TABLE III Autoclave Reaction Control Chloride Time,

Min. Tempera- Pressure,

ture, F. p.s.i.

A None 20 440 .300 B None 30 440 300 "wss'put into a hot press.Talblc'IV' sets fdrth' the 'spe- 9 cific press temperature, pressure andtime cycles that were used for the various reaction products. Ingeneral, the above procedure produced boards of approximately l 4% inchthickness, depending upon the reaction prodlyst was then added to theblend in the same manner as specified in Example 16 and the mixture wasball-milled for an additional /2 hour in order to thoroughly dispersethe catalyst throughout the mass. Both the amounts net. The density ofthe boards was determined and they of the additive and the chlorides areby weight of the ligwere tested in both a one hour boil and a 48 hourimnocellulose. mersion in room temperature water to obtain their mois-To determine the effect of the chlorides, controls'were ture absorptionand their dimensional stability. In addirun in which Viusol, lignin andphenolic residue were tion, the boards were tested in flexure todetermine their blended with the lignocellulose in the same manner asmodulus of rupture. The results of these tests are also specified inExamples -45, and the mixtures were then lncluded in Table IV.autoclaved without the addition of a chloride. Table VI TABLE IV PressConditions Increase From Increase From Boil Test Hour Density, M.R.,Immersion Product Example Percent Chloride lb./tt. 3 p.s.i

4 Time, Tem Press Min. F. p.s.l. Wt., Thick, we. Thlck., percent percentpercent percent None 10 300 100 51.0 472 Delaminated 58.5 10.2 ....d(:10 400 42.5 393 74.8 16.5 75.5 5.2 do 10 300 100 39.6 70 Delaminated88.6 8.3 an 10 400 40 39.0 247 92.3 19.7 84.8 4.9 %%Aluminum 10 300 10062.6 1,414 17.8 a 7.17 17.8 2.1 do 10 400 40 58.0 1,309 25.7 3.4 37.81.7 34% Titanium.---- 10 400 40 35.4 95 95.9 8.7 102.4 6.9 2% Manganese10 400 40 47.0 287 53.3 5.6 51.5 2.2 1% Copper 10 400 40 55.5 552 37.53.5 39.5 2.9 1% Iron 10 300 100 62.8 1,020 25.1 9.8 18.2 2.5 do 10 40040 57.6 1,445 27.4 5.0 30.7 3.8 21. 2% Iron 10 400 40 63.7 1,134 13.51.7 18.5 1.3 22 1% Ammonium-.. 10 400 40 46.4 313 35.1 1.9 44.7 0.3 231% 7m 10 400 40 40.5 514 83.5 6.3 84.2 3.7 24 2% Zinc 10 400 '40 38.5304 81.7 5.0 87.9 3.5 25 1% Calcium 10 400 40 45.1 527 54.7 6.1 67.2 3.725 2% Calcium 10 400 40 53.2 575 42.2 4.7 43.9 2.3 27 2% Magnesium 10300 100 63.5 1,959 26.1 13.3 19. 5 3.3 27- d0 10 400 40 51.3 800 41.15.4 43.9 2.7 28 2% Potassium-.-" 10 400 40 48.2 773 67.6 13.7 54.5 4.829 Acetyl 10 400 40 52.2 1,050 48.8 9.2 42.7 4.9

An examination of the properties in Table IV shows sets forth thecomposition and conditions under which the that both control boards Aand B were relatively very controls were run. weak products, had highwater absorption, and had very TABLE VI poor dimensional stability asindicated by the increase 40 in thickness in both the boil and 48-hourimmersion tests. Autoclave The boards made from the chloride catalyzedreaction c mm Rea on Example Additive Time products of Examples 16-29had lmproved strength, Tempem Pressure, as shown by the modulus ofrupture, lower water abture, F, ps1, sorption, and marked superiority indimensional stability 45 in both boil and immersion tests. 5;; X31561 26440 300 5 ignin 20 440 300 Improvements in dlmenslonal stability,strength, and 2 Phenolic Residue" 20 440 300 compressibility can also beobtained by condensing hlgh molecular weight aromatic materials with thelignocellulose in the presence of a chloride catalyst. Examples Theautoclaved materials from Examples 30-45, and 30-45 in Table Villustrate the reaction conditions emcontrols C, D, and E were pressedinto boards in the TABLE V Autoclave Reaction 7 Example ChlorideAdditive Time,

Min. Tempera- Pressure,

ture, F. psi.

1% Ferric 5% Vinsol 20 440 300] do 6% Lignin 20 440 300 5% PhenolicResidue- 20 440 300 5% Vinsol '15 440 300 5% Lig'nin .15 440 300 5%Phenolic Residue- 15 440 300 5% Vinsol 20 440 300 37 5% 16m 15 440 30038 do 5% Phenolic Residue 15 440 v 300 39 2% Calcium 5% Vineol 25 440300 40 d0 20 440 300. 41 d6 15 440 300 42.. 35% Ammon1um 20 440 300 43..-do 5 Lig'niIl 20 440 300 44.- do 5% Phenolic Residue.. 20 440 300 45.2% Manganese--.. 5%Vins0l 20 440 a 300' ployed withexamples usinglignin, Vinsol, and phenolic residue in cnojunction with the chloridesas catalysts. In these examples a dry blend of the finely dividedreactant, and the lig'nocellulose was made by ball-milling the two 7ingredientsfor /2 hour. ,The aqueous solution of-cataare set forthin'lableVlI'beloww -'of these tests, together with th manner specified rExamples 15-29, and rzthe boards were evaluated by testing 'formoistureabsorption, di-

mensional stabilityand strength in flexure'. vThe results.

utilizing phenol and cresol.

TABLE VII Increase From Increase From Press Conditions Boil Test 48 HourIm- Deumersion Prod. Percent Chloride Additive Sity, Exam. 1b./ft.13.5.1

Time, Temp., Press, Wt., Thick, Wt., Thiek.,

Min. F. p.s.i. Per- Per- Per- Percent cent cent cent 5% Vinsol 10 400 4050. 917 61. 8 14. 54. 8 4. l3 5% Lignin 400 40 47. 0 625 65. 3 11. 262.9 4. 2 5% Phenolic Residue-. 10 400 40 51. 5 818 57. 7 22. 0 50. O 5.5 5% Vinsol 10 400 40 62. 2 1, 107 18.0 3. 2 23. 9 1.1 5% Lignin 10 40040 50. 7 816 42. 9 2. 4 4.8. 0 1. 7 5% Phenolic Residue 10 400 40 55. 31, 389 25. 8 4.1 31. 4 2.1 5% Vinsol 10 400 40 52. 3 1, 106 44. 9 5. 744. 9 2. 7 5% Lignin 10 400 40 39. 2 412 83. 2 4. 1 87. 3 2. 8.-...do... l 5% Phenolic Residue..- 10 400 40 50. 8 1, 162 43. 7 5.1 34.5 2.1 2% Magnes 5% Vinsol 10 400 40 55. 2 971 36. 1 3. 8 28. 1 1.1 37--.-.-.do.-. 5%.Ligni11 10 400 40 57.1 76 33.1 4. 5 27. 1 1.0 38. .-.-.do5% Phenolic Residue..- 10 400 40 62. 0 1, 804 19. 7 4. 1 16. 4 1. 3 39.2% Calcium. 5% Vinsol 10 400 40 49. 8 940 46. 3 5, 1 50. 7 2. 6 40.----.d0... 5% Lignin 10 400 40 54. 0 722 45. 4 4. 3 44. 3 1. l) 41..-...tlo....- 5% Phenolic Rcsidue.- 10 400 40 G1. 5 1, 819 28.1 6. 4 27.9 2. 7 42-- Ammon1um-- 5% Vinsol. 10 400 40 55. 3 875 39.2 7.1 37. 1 2.8 43. -...-do 5% Lignin 10 400 40 55. 5 1, 488 34. 6 7. 1 36. 4 3. 744.- -....do 5% Phenolic Residue-. 10 400 40 56.0 1, 2 29.9 7. 6 39.3 3.3 45.--.. 2% Manganese..-. 5% Vinsol 10 400 40 49. 3 7 44. 5 2. 3 49.7 1. 2

From a comparison of the physical properties of the boards listed inTable VII it is'apparent that the strength of the boards is improved,and both the moisture absorption and dimensional stability are improvedwhen a chloride is used as -a catalyst in the condensation of these highmolecular weight materials with lignocellulose. Depending upon thechloride and additive used, reaction products are produced possessing awide rangeof properties.

When phenols are condensed with lignocellulose, in the presence of steamutilizing "a chloride catalyst, the plasticity of the reaction productis improved. Thus where materials are desired for high pressure moldingor extrusion, phenols may be included in the reaction to obtain a higherdegree of flow in the molding or extrusion operation. Table VHI setsforth examples of reactions The quantities of chloride and additivesshown are by weight of the lignocellulose.

corresponding compositions, autoclave conditions and reaction times, butwithout the addition of a phenol, are

In all examples of Table IX the press temperature was 300 F. and thepress pressure was 5000 p.s.i.

The observed flow times listed in Table IX indicate that thecondensation of phenols with lignocellulose in the presence of achloride improves the plasticity of the In order to obtain a relativemeasure of flow, and to evaluate the effect of the phenols onplasticity, ten gram quantities of the reaction products were placed ina 2-inch diameter cylinder, and a piston was placed on top of thematerial. Both the cylinder and the piston were heated to 300 F. Thisassembly was then placed in a press maintained at 300 F. and the presswas closed until the pressure on the. material was 5000 psi. The timerequired for the material to. extrude out from underneath the bottom ofthe cylinderaon the platen was then ob- Iserved, and useda as arneasureof-the relative plasticity.

The results of this test fonExatnple's: 46-48; as w'ellas'forcontrols F,G, and H, which are antoclaved materials of material, even when phenolsare used in'only small'quantities.

Where materials are required that exhibit less moisture absorption, andgreater dimensional stability than the chloride catalyzed lignocellulosereaction with steam, fatty acids such astall oil, butyric, etc. can beused and they appear toesterify-some-of the alcoholic functional groupsin the lignocellulose. 'I-Iere again the chlorides appear to function ascatalysts, In general where fatty acids are employed, somewhat lowerpressures or shorter reaction times' maybe used in processing thematerial. Table X sets forth the conditions under whicha number of thechlorides have been used in conjunction with fatty acids.

- TABLE X Autoclave Reaction Example Chloride Additive Time,

Minutes Temp., Pressure,

F. p.s.i.

- 1% Aluminum- Tall Oil 5 400 200 -----do 5 400 200 20 400 200 440 300The autoclaved materials in Examples 49-55 were pressed into boards andevaluated in the same manner as specified for Examples 16-29. Thephysical properties obtained and the press conditions employed arelisted in The chlorides also appear to promote a wide variety of otherreactions with lignocellulose, such as reaction with unsaturatedcompounds, alcohols, and elemental sulfur. The properties of suchreaction products vary Table XI. 20

TABLE Xi Press Conditions Boil Test 48-Hour Immersion Prod. PercentDensity, M.R Exam. Chloride Additive lb. p.s.i

Time, Temp., Press., Wt., Thick., Wt., Thick Min. F. p.s.i. Per- Per-Per- Percent cent cent cent 10% Tall Oil.. -10 400 40 65.0 1,483 10 4 0.8 16.6 0.8 10% Butyric A 10 400 40 63. 5 1, 570 22 1 2. 9 21. 6 2. 2 5%Tqll Oil. 10 400 40 56.0 1,292 9 5. 1 36. 3 3. 6 2%% Tall Oil 10 400 59.0 1, 360 24 2 3. 4 24. 1 1. 9

Butyric Anhydride. 53---" 1% Zinc 5% Tall Oil 10 400 40 60. 5 908 43. 23. 1 34.1 1. 9 54 3% Calcium..- 5% Vinsol 3% Tall 10 400 40 60. 7 1, 09910. 3 2. 1 12. 6 1. 7 1% Acetyl 10% Tall Oil 10 400 40 65.0 1, 717 17. 13. 8 18. 9 3. 2

A comparison of the physical properties of the boards produced inExamples 49-55 with those listed in Tables IV and VII for similarcompositions, but without a fatty .acidlindicate that the dimensionalstability is improved 40 autoclaved.

widely, depending upon the specificrreactant used. Table XII sets fortha number of representative reactions along with the conditions underwhich the materials were even though generally milder reactionconditions were used in processing the materials. The boards themselvesappear to be somewhat. softer, and more resilient when 7 long chainfatty acids are usedin the esterification of the 7 Similarly to theprevious examples, the materials from; L

Examples 56-61 were: pressed into boards'as specified for Examples16-29, andthe boardswere evaluated'IfThe" physical propertiesobtained'along with the'press condihgnocellulose. 60 tlons employed arelisted in Table XIII.

TABLEXIIL 1 v Increase From Increase From 7 Press Conditions 1 Boil TestS-Hour Immersion. Prod. Chloride Additive Density, M.R., V w Exam.1b./ft. p.s.i. p

Time, Temp., Press, Wt, Thick., Wt., Thick.,

Min. F. p.s.i. Per- Percent Percent cent 1% Aluminum 10%Dicyclopentadiene 10 300 69.6 2,030 12.2 5.2 34% Aluminum. 10% StyreneMonomer. 10 400. 40 67. 5 1,096 13. 4 2.1 -'.do 10%Isopropy1Alcohol 10400 40 i 43.7 349 54.9 2.6 -;do. 10% G1ycerine- 10 400 71.0 1,319 8.56.3 1% Ferric. 6% Sulfur--- 10 400 40 41.1 667 78.7 3.9 1% Zinc .-do 10400, 40 50.0 508 38.0 3.;1

Percent i i '15 From the densities of the boards listed in Table XIII itis apparent that although the dimensional stabilities are fairlyequivalent, the plasticity of the materials varies considerably. Thuswhere a higher degree of plasticity '16 bodiments set out herein, it ismy intention that the invention be not limited by any of the details ofdescription unless otherwise specified, but rather be construed broadlywithin its spirit and scope as set out in the accomis required toproduce a finished product, those reactions panying claims. producingthe denser or more plastic materials can be I claim: used; while theless plastic can be used for lighter weight 1. The method of making amoldable lignocellulose products that have high relative dimensionalstability. product, consisting essentially of: intimately mixing fine-If desired the reaction products that are disclosed in ly dividedlignocellulose material with about (Ll-50% of this invention can beblended with various fibers and a chloride catalyst capable ofcatalyzing the conversion fillers as well as with thermoplastic resins.In general of at least a portion of the lignocellulose to a materialwhere organic fillers are used the moisture absorption capable of beingconsolidated under heat and pressure; will increase, however, Within therange of filler addition and heating said mixture in a confinedatmosphere in the specified. The dimensional stability is notappreciably presence of moisture at a pressure of about 25-700 changed.Where thermoplastics such as vinyl chloride pounds per square inch gaugeand a temperature of resins are blended with these materials, thestrength is about 250-500 F. for about 4-60 minutes, said per--increased, and both the moisture absorption and dimencentage being byweight of the lignocellulose.

sional stability appear to be improved. Table XIV lists 2. The method ofmaking a moldable lignocellulose a number of representative compositionswhich have been product, consisting essentially of: intimately mixingfinely blended with fillers and thermoplastics by ball-milling thedivided lignocellulose material with about 0.l-50% of a two materialstogether for 15 minutes prior to pressing chloride catalyst capable ofcatalyzing the conversion of the blends into boards. The amount offiller employed at least a portion of the lignocellulose to a materialis based on the weight of the autoclave reaction products. capable ofbeing consolidated under heat and pressure,

TABLE XIV Autoclave Material Autoclave Conditions Exam. No. Filler,Fiber or Thermoplast Chloride Additive Time, Temp., Press,

Min. F. p.s.i.

3% Calcium." 20 440 300 %50 Mesh Wood Flour. ..d 20 440 300 10%-50 MeshWood Flour.

2 400 300 155 1-20 Mesh Hydrolyzed Wood Our. 20 440 300 10%-200 MeshBagasse. 20 440 300 25% Asbestos. 20 440 300 25% Pearlite.

15 400 200 3% Vinyl Chloride. 2% Zinc 15 440 300 5% Vinyl Chloride.

2% Calcium--- 20 440 300 -Do.

Table XV lists the properties obtained and press conditions used for theboards of Examples 62-70.

said chloride being a member of the class consisting of titanium,aluminum, copper, iron, ammonium, zinc,

TABLE XV Increase From Increase From Press Conditions Boil Test 48-HourIm- Density, M.R mersion Prod. Exam. Filler or Thermoplest lbs/it. p.s.i

Time, Temp., -Press, Wt., Thick, Wt., Thick,

Min. -F. p.s.i. .A Percent Percent Percent Percent 25% Wood Flour 10 40053, 5 882 40. 6 4. 4 33. 4 2. 7

10% Wood Flour 10 400 40 58.8 1, 712 27. 9 3. 7 28. 2 2. 4

15% Hydrolyzed Wood 10 400 40 53. O 668 36. 4 5. 3 32. 1 O. 6

25% Asbestos 10 400 40 73. 5 2, 026 16. 6 1. 9 14. 7 1. 2

25% Pearlite.. 10 400 40 48. 2 622 30. 3 3.1 31.4 0.7

3% Vinyl Clilorid 10' 400 40 61. 8 2, 744 ll. 5 i 2. 7 16. 3 1. 3

5% Vinyl Chlorid 10 400 40 45. O 916 58. 6 2. 8 63. 7 1. 7 10 400 40-56. 5 l, 378 28. 4 2. 6 28.1 1. 2

'shouldalso be observed that even where as much'as' 25% of wood fiour isincorporated into the board, the dimensional stability still-remainsvery good.

-All percentages herein are by weight of the lignocellulose and allpressures are gauge. The immersion tests herein were all made in waterat room temperature.

Thephenolic residue used herein is essentially a condensation product ofphenol with acetone and alpha- 7 inethylstyrene.

Having described'm'y" iiiven'tionasrelated to the em manganese,magnesium, calcium, potassium and acetyl chlorides; and heating saidmixture in a confined atmosphere in the presence of moisture at a'pressure of about 25-700 pounds per square inch gauge and a temperatureof about 250500 F. for about 4-60 minutes, said percentage being byweight of the lignocellulose.

3. The method of making a moldable lignocellulose product, consistingessentially of: intimately mixing finely divided lignocellulose materialwith about 0.1-50% of a chloride catalyst capable of catalyzing theconversion of at least a portion of the lignocellulose to a materialcapable of being consolidated-under heat and pressure, andabout 230%oflignin; and heating said mixture in a'confined atmosphere in-thepresence of moisture at a pressure of'a'bout 25-700"pounds' per squareinch gauge 17 a and a temperature of about 250-500 F. for about 4-6minutes, said percentages being by weight of the lignocellulose.

4. The method of making a moldable lignocellulose product, consistingessentially of: intimately mixing finely divided lignocellulose materialwith about 01-50% of a chloride catalyst capable of catalyzing theconversion of at least a portion of the lignocellulose to a materialcapable of being consolidated under heat and pressure, and about 2-30%of a solvent extracted pine wood resin substantially free of wood rosin;and heating said mixture in a confined atmosphere in the presence ofmoisture at a pressure of about 25-700 pounds per square inch gauge anda temperature of about 250-500 F. for about 4-60 minutes, saidpercentages being by weight of the lignocellulose.

5. The method of making a moldable lignocellulose product, consistingessentially of: intimately mixing finely divided lignocellulose materialwith about 01-50% of a chloride catalyst capable of catalyzing theconversion of at least a portion of the lignocellulose to a materialcapable of being consolidated under heat and pressure, and about 1-20%of a phenol; and heating said mixture in a confined atmosphere in thepresence of moisture at a pressure of about 25-700 pounds per squareinch gauge and a temperature of about 250-500 F. for about 4-60 minutes,said percentages being by weight of the lignocellulose.

6. The method of making a moldable lignocellulose product, consistingessentially of intimately mixing finely divided lignocellulose materialwith about 01-50% of a chloride catalyst capable of catalyzing theconversion of at least a portion of the lignocellulose to a materialcapable of being consolidated under heat and pressure, and about 05-50%of a fatty acid; and heating said mixture in a confined atmosphere inthe presence of moisture at a pressure of about 25-700 pounds per squareinch gauge and a temperature of about 250-500 F. for about 4-60 minutes,said percentages being by weight of the lignocellulose.

7. The method of making a moldable lignocellulose product, consistingessentially of: intimately mixing finely divided lignocellulose materialwith about 01-50% of a chloride catalyst capable of catalyzing theconversion of at least a portion of the lignocellulose to a materialcapable of being consolidated under heat and pressure, and about 05-20%sulfur; and heating said mixture in a confined atmosphere in thepresence of moisture at a pressure of about 25-700 pounds per squareinch gauge and a temperature of about 250-500 F. for about capable ofbeing consolidated under heat and pressure;

and about 05-30% of an unsaturated organic compound;

and heating said mixture in a confined atmosphere in the presence ofmoisture at a pressure of about 25-700 pounds per square inch gauge anda temperature of about 250-500 F. for about 4-60 minutes, saidpercentages being by weight of the lignocellulose.

9. The method of making a moldable lignocellulose product, consistingessentially of: intimately mixing finely divided lignocellulose materialwith about 0.1-% of a chloride catalyst capable of catalyzing theconversion of at least a portion of the lignocellulose to a materialcapable of being consolidated under heat and pressure, and about 230% ofan alcohol; and heating said mix ture in a confined atmosphere in thepresence of moisture at a pressure of about 25-700 pounds per squareinch gauge and a temperature of about 250-500 F. for about 4-60 minutes,said percentages being by weight of the lignocellulose.

10. A lignocellulose product prepared by the method of claim 1.

11. A lignocellulose product prepared by the method of claim 3.

12. A lignocellulose product prepared by the method of claim 4.

13. A lignocellulose product prepared by the method of claim 5.

14. A lignocellulose product prepared by the method of claim 6.

15. A lignocellulose product prepared by the method of claim 7.

16. A lignocellulose product prepared by the method of claim 8.

17. A lignocellulose product prepared by the method of claim 9.

References Cited in the file of this patent UNITED STATES PATENTS2,156,160 Olson et a1. Apr. 25, 1939 2,379,889 Dorland et a1. July 10,1945 2,379,890 Dorland et a1 July 10, 1945 FOREIGN PATENTS 497,477 GreatBritain Dec. 16, 1938

1. THE METHOD OF MAKING A MOLDABLE LIGNOCELLULOSE PRODUCT, CONSISTINGESSENTIALLY OF: INTIMATELY MIXING FINELY DIVIDED LIGNOCELLULOSE MATERIALWITH ABOUT 0.1-50% OF A CHLORIDE CATALYST CAPABLE OF CATALYZING THECONVERSION OF AT LEAST A PORTION OF THE LIGNOCELLULOSE TO A MATERIALCAPABLE OF BEING CONSOLIDATED UNDER HEAT AND PRESSURE, AND HEATING SAIDMIXTURE IN A CONFINED ATMOSPHERE IN THE PRESENCE OF MOISTURE IN ACONFINED ATMOSPHERE IN THE POUNDS PER SQUARE INCH GUAGE AND ATEMPERATURE OF ABOUT 250-500*F. FOR ABOUT 4-60 MINUTES, SAID PERCENTAGEBEING BY WEIGHT OF THE LIGNOCELLULOSE.